Antioxidant



Patented Feb. 22, 1944 ANTIOXIDANT Carlin F. Gibbs, Cuyahoga Falls, Ohio, assignor to I The B. F. Goodrich Company, New York, N. Y.,

a corporation of New York No Drawing. Application December 10, 1942,

' Serial No. 468,549

' s Claims. (01. 260-808) This invention relates to the preservation of organic materials which tend to deteriorate by absorption of oxygen from the atmosphere, and the means for preventing such deterioration. This application is a continuation-in-part of my application Serial No. 405,791, filed August '7, 1941.

porating in the material to be preserved, as an antioxidant, a certain kind of 'alkenyloxy diarylamines. Among the materials which may be thus preserved are unsaturated fatty oils such as linseed oil or tung oil, petroleum-oils such as gasolines, soaps, aldehydes, synthetic resins, turpentine, fish oils, rubber, and the like.

Any of the natural rubbers such as caoutchouc, balata, gutta percha, latex, as Well as artificial rubber isomers, and such synthetic rubbers as the copolymers of butadiene with acrylonitrile, styrene, isobutylene, methyl acrylate, methyl methacrylate, and the like, whether vulcanized or unvulcanized, may have their resistance to light, heat, and air greatly increased by the incorporation of a small amount, from 0.1 to 5.0% or more, of my new compounds in the rubber composition. Th resistance of vulcanized rubber compositions to flex cracking is particularly improved by the use of these materials.

Specific examples of the materials which may be used as antioxidants include, among others,

B-beta-methallyl-4-methallyloxy-diphenylamine 2-methally1oxy-3-beta-metha11yl-diphenylamine 2-methallyloxy-diphenylamine 3-methallyloxy-diphenylamine 4-methallyloxydiphenylamine 4,4-diinethallyloxy-diphenylamine 4-methallyloxy-phenyl-alpha-naphthylamine -methyll-metha1lyloxydiphenylamine 4-methyl-phenylamino-4-methallyloxy-diphenylamine Y 4-anilino-4-metha11y1oxy-diphenylamine The antioxidants of my invention have the following general formula I A-O-R-NR'X where R and R are each an aryl radical singly bonded to O and N, and to N and X respectively. They are preferably further unsubstituted, but may contain as further substituents in the aryl nucleus such groups as the following: amino, halogen, secondary or tertiary alkylamino, secondary or tertiary arylamino, mercapto, alkyl mercapto, etc. Y is hydrogen, nitroso, or amino;

The method of my invention comprises incor- O is oxygen; N is nitrogen; A is an alkenyl group;

X is hydrogen or an aikenyloxy group. In either or both A and X the alkenyl group may be further substituted with maintenance of the unsaturated bond as by any of the following groups: halogen, amino, hydroxyl, secondary or tertiary alkyl amino, secondary or tertiary aryl amino, mercapto, alkyl mercapto, alkoxy, aryloxy.

The preferred class of substituted diarylamines have the structure where R is an aryl radical of the benzene, naphthalene, or diphenyl series singly bonded to N and 0 respectively; and A is an alkenyl radical singly bonded to the oxygen, having the general formula or in the case of an alkenyl group bearing a substituent, having the general formula:

portions of 10% alcoholic potash. The reaction is complete after the mixture has been refluxed for about two hours, and the product is separated by cooling the mixture, neutralizing it with acid, and filtering. The product may be recrystallized from alcohol.

Rearrangement of the methallyloxy diphenylamine to 3-beta-methallyl-4-hydroxy-diphenylamine is readily accomplished by heating the ether with about one-half its weight of diethylaniline as solvent for about thirty to fifty minutes at 200 C. Other solvents such as dimethylaniline or various hydrocarbons may also be used. The product may be separated from the reaction mixture by distillation at reduced pressure. The material boils at 165 to 175 C. at 3 mm. Similar compounds may be obtained by treating other beta-alkyl allyl ethers under similar conditions.

The compound 3-beta-methallyl-4-methallyloxy-diphenylamine is obtained by heating the foregoing hydroxy compound with one molecular equivalent of beta-methallyl chloride in the presence of about 1.5 molecular equivalents of alcoholic potash. The reaction is complete after refluxing for about two hours, and the product is separated by cooling the mixture, neutralizing it, and filtering,

When about one part by weight of either 4.-

methallyloxy diphenylamine or 3-beta-methallyl- 4-methallyloxy diphenylamine is added to a com-"- position containing 100 parts of rubber, 50 parts of carbon black, 5 parts of zinc oxide, 3 parts of sulfur, 3 parts of pine tar, 3.5 parts of stearic acid, and 1.0 part of mercaptobenzothiazole, and

the composition is vulcanized,.the resultant rub Although I have herein disclosed specific embodiments of my invention, I do not intend to limit myself solely thereto, but to embrace all the obvious modifications included within the scope of the appended claims.

I claim:

1. Method of preserving organic substances which tend to deteriorate by absorption of oxygen from the air which comprises incorporating therein a methallyloxy diarylamine.

2. Method of preserving organic substances which tend to deteriorate by absorption of oxygen from the air which comprises incorporating therein methallyloxy diphenylamine.

3. A method of preserving rubber which comprises incorporating therein a methallyloxy diarylamine.

bar stock retains its tensile strength and elonga tion at break to a much greater extent under severe aging conditions than does a similar vulcanized' rubber composition containing no antioxidant. Whereas the tensile strength of the rubber composition containing no antioxidant dropped from about 3800 to 4000 lb. per sq. in. to 1000 lb. per sq. in. or lower after a few days aging in oxygen at 300 lb. per sq. in. and at 70 C., .thetensile strength of similar rubber compositions containing these new antioxidants was considerablyover 2000 lb. per sq. in. after the same period of aging. The resistance of the rubber composition to flex cracking was also greatly increased by my antioxidants.

Any of the usual pigments, fillers, dyes, reinforcing, agents, softeners, accelerators, vulcanizing agents, other antioxidants, or the like may also be present. Rubber compositions containing these new antioxidants may be used for a variety of purposes, such as tires and tubes, hose, belting, molded goods, and the like. Such compositions may be vulcanized by any of the usual methods, such as issteam, hot air, or in a mold.

4. A method of preserving rubber which comprises incorporating therein a 4-metha1lyloxy diphenylamine,

5-. Amethod of preserving organic substances which tend to deteriorate by absorption of oxygen from the air which comprises incorporating thereina compound having this formula 

